Android自定义仿ios加载弹窗

public class IosLoadDialog extends Dialog {

    public IosLoadDialog(Context context) {
        super(context, R.style.loading_dialog);
        initView();
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        switch (keyCode){
            case KeyEvent.KEYCODE_BACK:
                if(IosLoadDialog.this.isShowing())
                    IosLoadDialog.this.dismiss();
                break;
        }
        return true;
    }


    private void initView(){
        setContentView(R.layout.dialog_loading);
        Animation animation = AnimationUtils.loadAnimation(getContext(), R.anim.load_animation);
        animation.setInterpolator(new LinearInterpolator());
        findViewById(R.id.loading_dialog_img).startAnimation(animation);

        setCanceledOnTouchOutside(true);
        WindowManager.LayoutParams attributes = getWindow().getAttributes();
        attributes.alpha=0.8f;
        getWindow().setAttributes(attributes);
        setCancelable(false);
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/dialog_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/tm"
    android:gravity="center"
    android:minHeight="60dp"
    android:minWidth="180dp"
    android:orientation="vertical"
    android:padding="10dp">

    <LinearLayout
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:background="@drawable/white_radian13"
        android:gravity="center"
        android:orientation="vertical">

        <ImageView
            android:id="@+id/loading_dialog_img"
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:scaleType="fitXY"
            android:src="@drawable/ic_svstatus_loading" />
    </LinearLayout>

</LinearLayout>

<style name="loading_dialog" parent="android:style/Theme.Dialog">
        <item name="android:windowFrame">@null</item>
        <item name="android:windowNoTitle">true</item>
        <item name="android:windowBackground">@color/tm</item>
        <item name="android:windowIsFloating">true</item>
        <item name="android:windowContentOverlay">@null</item>
    </style>

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape>
            <solid android:color="#F7FBFD" />
            <corners android:radius="13dp" />
        </shape>
    </item>
</layer-list>

public void showDialog(){
        final IosLoadDialog iosLoadDialog = new IosLoadDialog(this);
        iosLoadDialog.show();
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                iosLoadDialog.dismiss();
            }
        },1200);
    }